Annulus-reinforcing band

ABSTRACT

A pliable band or hoop that is flexible to normal handling, but cannot stretch circumferentially once it has reached the limits of its circumferential length. The band may have a structural portal to be used for filling, or it may simply be constructed of a fabric-like material that allows a fill tube to perforate its walls to allow for filling. In the latter case, the perforated wall tends to self-seal once the fill tube is withdrawn. The band may be flat or tubular in cross-section. However, unlike a balloon, the band does not require either a bottom or a top, as we found that a top and bottom are unnecessary when using a band or hoop to enclose material injected into a reamed out intervertebral space.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 11/447,615 filed Jun. 6, 2006 which is a continuation application ofU.S. application Ser. No. 10/812,345 filed Mar. 29, 2004 which is acontinuation application of U.S. application Ser. No. 10/022,048 filedDec. 17, 2001, and now U.S. Pat. No. 6,712,853, which claims priorityfrom U.S. provisional application No. 60/256,014, filed Dec. 15, 2000,the entire contents of which are incorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

Not Applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to devices that provide a means to support and/orreinforce and/or stabilize a diseased mammalian spinal intervertebraldisc.

2. Description of the Related Art

It is recognized that the spinal disc consists of three parts: first,the nucleus, a central portion that is a compression-resisting cushion;second, the annulus, a peripheral rim portion that is atension-resisting hoop; and third, the end plate, the superior andinferior borders of the disc, consisting of the up and down borders ofthe vertebral body bones.

Many studies have concluded that mechanical back pain is the most commonand costly musculoskeletal condition affecting middle-aged humans inmodern societies. Mechanical back pain may be caused by several factors,but overwhelming evidence suggests that degeneration of the spinalintervertebral disc, such as may be caused by Degenerative Disc Disease(DDD) is the most common condition causing back pain symptoms.

The inventor, in a previously published work entitled the tissue originof low back pain and sciatica: A report of pain response to tissuestimulation during operations on the lumbar spine using localanesthesia. (Orthop. Clin. North Amer. 1991; 22(2):181-187.),demonstrated that the diseased disc rim or annulus is the principle paingenerator responsible for mechanical back pain.

Many devices have been invented for the purpose of stabilizing and/orreplacing parts of the disc in an effort to ease the pain associatedwith disc disease. Indeed, one of the author's prior inventions, the BAKhas been used in more than 80,000 humans, with generally good results(See generally: the Bagby and Kuslich Method of Lumbar Interbody Fusion.History, Techniques, and 2-year Follow-up Results of a United StatesProspective, Multicenter Trial. Kuslich S. D., Ulstrom C. L., GriffithS. L., Ahem J. W., Dowdle J. D., Spine 1998; 23:1267-1279; Summary ofSafety and Effectiveness Of the BAK Interbody Fusion System, Food andDrug Administration (FDA) (PMA 950002), PMA Document Mail Center(HFZ-401), Center for Disease and Radiological Health, Washington D.C.,Sep. 20, 1996; and Lumbar Interbody Cage Fusion for Back Pain: an Updateon The BAK (Bagby and Kuslich) System, Kuslich S. D., Spine: State ofthe Art Reviews 1999; 13(2):295-311). Unfortunately, the BAK and manysimilarly structured rigid metallic implants suffer from several lessthan ideal features such as: the need to create fairly large surgicalexposures, the need for fairly large entrance holes through the annulusof the disc, and the presence of fairly large volumes of metal thatreduce bone graft surface contact at the end plate.

Any device that would more easily, and/or more effectively, and/or moresafely treat degenerative disc disease would be useful in the managementof hundreds of thousands of suffering individuals.

Previous patents involving intervertebral devices designed to treat DDDfall generally into the following four classes:

The first class includes rigid, three-dimensional geometric soliddevices, either impervious or porous, that function as support struts.When placed in the area of the disc between adjacent vertebral bodies,they allow and/or encourage bone to grow through and/or around thedevice to cause a bony fusion between two adjacent vertebral bodies.Examples of such devices have been described in the followingreferences:

U.S. Pat. No. 6,015,436 to Schonhoffer

U.S. Pat. No. 6,010,502 to Bagby

U.S. Pat. No. 5,972,031 to Biedermam et al.

U.S. Pat. No. 5,895,427 to Kuslich

U.S. Pat. No. 5,735,899 to Schwartz et al.

U.S. Pat. No. 5,720,748 to Kuslich

U.S. Pat. No. 5,709,683 to Bagby

U.S. Pat. No. 5,700,291 to Kuslich

U.S. Pat. No. 5,669,909 to Zdeblick

U.S. Pat. No. 5,514,180 to Heggeness et al.

U.S. Pat. No. 5,591,235 to Kuslich

U.S. Pat. No. 5,489,308 to Kuslich

U.S. Pat. No. 5,489,307 to Kuslich

U.S. Pat. No. 5,405,391 to Henderson et al.

U.S. Pat. No. 5,263,953 to Bagby

U.S. Pat. No. 5,059,193 to Kuslich

U.S. Pat. No. 5,015,255 to Kuslich

U.S. Pat. No. 5,015,247 to Michelson

U.S. Pat. No. 4,946,458 to Harms et al.

U.S. Pat. No. 4,936,848 to Bagby

U.S. Pat. No. 4,834,757 to Bantigan

U.S. Pat. No. 4,820,305 both to Harms et al.

U.S. Pat. No. 4,501,269 to Bagby

U.S. Pat. No. 4,401,112 to Rezaian

The second class involves the use of semi-rigid artificial joints thatallow motion in one or more planes. Examples include U.S. Pat. No.4,759,769 to Kostuik, U.S. Pat. No. 6,039,763 to Shelokov, andcommercially available examples such as the Link device or ChariteIntervertebral Disc Endoprosthesis.

The third class is directed to non-rigid cushions designed to replacethe nucleus of the disc. Examples of artificial discs are described inU.S. Pat. No. 4,904,260 to Ray, U.S. Pat. No. 4,772,287 to Ray and U.S.Pat. No. 5,192,326 to Boa.

Finally, the fourth class is the relatively new area of initiallyflexible, expandable bags or balloons that become rigid when injectedwith materials that can support loads. Examples include U.S. Pat. Nos.5,571,189 and 5,549,679 to Kuslich, each of which describe expandable,porous balloons or bags, useful in stabilizing a deteriorating spinaldisc. In this fourth class, a porous bag or balloon is used which isclosed except for a mouth through which bone graft or other graftmaterial is inserted. The bag is placed into a reamed out intervertebralspace and is expanded by the introduction of graft material. Recentresearch and development in the inventor's laboratory established thefact that a thin walled band or hoop, either porous or non-porous, canbe placed in the region of the annulus by means of several techniques.Such a band or bands as described in detail below effectively reinforcethe annulus and thereby support spinal motion segment strain deflectionsresulting from stresses applied in all vector directions: rotation,flexion-extension, side bending, compression and distraction.Furthermore, the inventor's experiments show that these radially appliedbands or hoops can effectively contain and retain inserted or injectedmaterials that are placed in the central region of a reamed-out disc.The current invention teaches a technique for building and using asimple band to perform many of the functions of the prior art describedabove. For instance, if compared to metal cylindrical implants such asdescribed in U.S. Pat. No. 5,015,247 to Michelson and metal-walled orplastic-walled rectangular shaped implants such as may be described inU.S. Pat. Nos. 4,878,915 and 4,743,256 both to Brantigan, the bands ofthis invention are softer, lighter, more pliable, and without hard sharpedges, thereby offering greater safety during passage next to delicatestructures such as the great vessels or the spinal cord. Also, thecompletely open structure at the Polar Regions adjacent to cancellousbone of the vertebral bodies, would allow for a more intimate fitbetween inserted graft material and living bone. This intimacy ofcontact, without any intervening implant material, may reasonably leadto a faster and more complete biological ingrowth through the centralportion of the implant.

It is well known that greater surface area contact between graft andliving bone is conducive to higher fusion rates and conversely, lowernon-union rates. Thus, the current invention provides for several uniqueadvantages over prior art in the field of interbody fusion devices.

In addition to its uses and advantages in the form of improved interbodyfusion devices, the attributes of the current invention would provide anew and potentially superior technology in two other categories oftreatment for degenerative disc disease: one, soft tissue reinforcementof diseased discs, and two, disc replacement.

In regard to soft tissue reinforcement of diseased discs, several newtechniques have recently become available to treat early and mid-stagedisc degeneration by methods less invasive and less drastic than fusionsurgery. Examples include: annular tissue modulation by heat application(See generally: Saal J. et al. North American Spine Societypresentations 1999, 2000); the use of a polyester tension band placedaround and between pedicle screws above and below the involved disc suchas, described in U.S. Pat. No. 5,092,266 to Graf; and combined tensionand distraction devices placed between pedicle screws, such as may beseen in the commercially available DyneSyS.υ. device from SulzerOrthopedics Ltd. While early results from the above technologies appearpromising, the current invention would obviate some of the potentialdangers and drawbacks of these systems. For example:

In the case of annular tissue modulation by heat application, thecurrent invention does not require heat. Heat can be injurious to localspinal nerves and vessels, possibly leading to paralysis or even deathby hemorrhage. The current invention immediately stabilizes the annulus,rather than having to wait until the heat-damaged tissue heals andshrinks.

In the case of a polymeric tension band placed between pedicle screwsabove and below the involved disc, the current invention does notrequire the placement of pedicle screws. The placement of pedicle screwsrequires a significant surgical exposure with attendant bleeding andinjury to local muscular, ligamentous, vascular and nervous tissues. Thecurrent invention can be installed through much smaller, microsurgicalexposures that would have less likelihood of causing collateral damage.

In the case of combined tension and distraction devices placed betweenpedicle screws, the current invention directly stabilizes the verytissue that is causing the discogenic pain, the annulus, rather thanattempting to stabilize the annulus by an external, cantilevered systemthat has all of the risks and disadvantages of using polyester tensionbands and pedicle screws.

The current invention is a basic departure from the prior art at a veryfundamental level. The core element of the invention is the simple butbroad concept of applying a tension-resisting circumferential band at ornear the mid or outer circumference of the annulus. A careful review ofthe patent and medical literature and prior art did not provide aninstance of this fundamental concept having been previously described.Once conceived, the core idea of using a circumferential tension band toreinforce an injured disc annulus led to a number of alternativeembodiments, spanning the treatment options all the way from simplereinforcement, to containment of graft material for interbody fusion, toradial containment of a centrally placed compressible or incompressiblenuclear replacement material. In other words, the basic concept of thecurrent invention could provide the critical element that would allow adeveloper and/or a surgeon a new means to structure a new andpotentially better annular support for a less invasive early tomid-stage degenerative disc disease treatment method. The inventionwould also provide an improved means of graft support for a lessinvasive interbody fusion method. Finally, the invention would providean improved means of support for nuclear material (biological ornon-biological, bioactive or inert, hydrophilic or non-hydrophilic,granular or amorphous)—for nuclear replacement or so-called artificialdisc replacement.

The entire content of each and all patents, patent applications,articles and additional references, mentioned herein, are respectivelyincorporated herein by reference.

The art described in this section is not intended to constitute anadmission that any patent, publication or other information referred toherein is “prior art” with respect to this invention, unlessspecifically designated as such. In addition, this section should not beconstrued to mean that a search has been made or that no other pertinentinformation as defined in 37 C.F.R. .sctn. 1.56(a) exists.

SUMMARY OF THE INVENTION

The invention provides for an expandable tubular member or band whichhas side walls and may include a fill opening. However, the expandableband does not require either a bottom or a top as it has been found thata suitable enclosure is created by placing such a band within a reamedout intervertebral space. Pressure within the interior of the band isexerted primarily against the side walls and the adjacent vertebraesurfaces. The pressure exerted by the bone graft material at the top andbottom is exerted against the exposed bone of the adjacent vertebraewhich encourages bone growth through the band interior. The bone graftmaterial is contained within the tube by a combination of the naturalbony top and bottom together with the sidewall of the band.

The current invention provides a novel means to support the diseasedand/or weakened annulus of the disc. This support would offer improvedresistance to stresses placed on the spine and therefore wouldreasonably result in decreased pain and improved function to anyindividual suffering from the degenerated disc disease condition.

In addition to simply reinforcing the diseased annulus of the disc, thedevices based on the invention herein described could also provide ameans to retain and contain materials that might be inserted or injectedinto the disc in an attempt to heal the annulus, to replace the naturalnucleus, or to create a bony fusion between the two adjacent vertebralbodies.

In at least one embodiment of the invention, the invention provides aflexible implant that may be inserted into a cavity formed in adegenerating disc. The flexibility of the band allows it to be insertedthrough a relatively small opening in a disc or vertebral space. Theband is then positioned so its fill opening, if any, may receivebiological fill material. This material is packed into the interiorflexible band, causing the band to expand and conform to the cavityformed in the disc or vertebrae. Fill material is added until enoughmaterial is present to expand the disc to the desired position. At thistime, the band fill opening is closed to prevent egress of the fillmaterial.

In at least one embodiment of the invention, the invention provides fora pliable band or hoop that is flexible to normal handling, but cannotstretch circumferentially once it has reached the limits of itscircumferential length. The band may have a structural portal to be usedfor filling, or it may simply be constructed of a fabric-like materialthat allows a fill tube to perforate its walls to allow for filling. Inthe latter case, the perforated wall tends to self-seal once the filltube is withdrawn. The band may be flat or tubular in cross-section.However, unlike a balloon, the band does not require either a bottom ora top, as we found that a top and bottom are unnecessary when using aband or hoop to enclose material injected into a reamed outintervertebral space.

As long as the width of the band is approximately equal to the annulusheight (or stated another way, the distance from one vertebralperipheral end-plate to its neighbor) the band serves well to containparticulate material inserted into the center of the disc cavity,without the need for a complete spherical enclosure, as would beprovided by a balloon. Since in the case of the reamed out interdiscalcavity, the top opening and bottom opening of the band would be coveredby dense vertebral bone, it is not necessary to enclose insertedparticulate graft or other material in these regions.

Pressure within the cavity, as would occur when a surgeon injectsmaterial into its central region interior to the band, is exertedradially against the band and the adjacent vertebral surfaces. As theinternal cavity is filled with incompressible material, such as bonegraft or bioceramic beads or granules, radial displacement beyond thecircumference of the band is restricted. Therefore, any additionalinjected material would be directed north and south against thevertebral bodies. This action would increase the distance between thevertebral bodies, and produce a so-called disc distraction. Thisdistraction is known to have three salutary results. First, itstabilizes the motion segment by tightening the ligamentous structures.Second, it opens the exiting holes for spinal nerves—the so-calledneural foramina—and thus relieves certain types of nerve compressiondisorders. Third, this improved stability is necessary to allow for bonyingrowth and through-growth, to produce an interbody fusion. Thepressure exerted by the bone graft material at the top and bottom isdirected against the exposed bone of the adjacent vertebra. Thisproduces an intimate contact that encourages bone growth through theinterior of the cavity.

In at least one embodiment, the invention consists of any continuousband or ring that would be placed around and near the outer margin ofthe intervertebral disc. A suture or preferably a flattened, braided orwoven strand or cord, for instance, that was placed circumferentiallyabout a disc and tied to make a tension-resisting ring, would qualify.Modern endoscopic surgical tools, combined with sophisticated surgicalnavigation systems make this option more practical and safer than wouldhave been possible a few years ago.

In yet another embodiment, the band would be pre-formed to match theanatomy of the patient. It would also be available in a variety ofcircumferences, plies, thicknesses, widths (in the superior-inferiordimensions), weave patterns, materials and filament diameters. The bandwould be flexible enough to fit through a small hole made in theannulus, such as during a routine disc hernia removal operation. Afterremoval of the disc hernia, the surgeon would introduce an expandablereamer and thereby remove the degenerated nucleus, the cartilage endplate, and the inner annulus, leaving the outer annulus intact. Examplesof such a procedure and expandable reamers are described in U.S. Pat.No. 5,445,639 to Kuslich et al. and co-pending U.S. Pat. App. Ser. No.60/182,610 to Kuslich et al., filed Feb. 15, 2000, the entire contentsof both being incorporated herein by reference.

The properly sized band would be pushed through the disc portal,whereupon, owing to its inherent springiness, or as a result of materialbeing injected in the interior of the disc, the hoop or band wouldexpand radially against the outer annulus. Perforating the mesh fabricof the band, by means of a pointed fill tube, would allow the surgeon tofill the cavity with significant pressure using graft material; perhapsby the use of a graft injection system such as described in a co-pendingU.S. patent application Ser. No. 09/738,726 filed Dec. 15, 2000 andentitled Tool to Direct Bone Replacement Material, to Kuslich et al.,and is a continuation in part application of U.S. patent applicationSer. No. 09/608,079 the entire contents of both being incorporatedherein by reference. The resulting compressed graft, held from furtherexpansion by the vertebral bone above and below, and the band or hoopradially, would change phase from liquid-like to solid-like, as is knownto occur when granular materials are subjected to compression loading(See: Friction in Granular Flows, by H. M. Jaeger, Chu-heng Liu, S. R.Nagel and T. A. Witten, Europhysics Lett. 11, 619 (1990); GranularSolids, Liquids, and Gases, by H. M. Jaeger, S. R. Nagel and R. P.Behringer, Rev. Mod. Phys. 68, 1259 (1996); and IUTAM Symposium onSegregation in Granular Flows (Solid Mechanics and its Applications),Vol. 81, October 2000). This phase change has been observed andscientifically characterized by our laboratory experiments and by thework described in U.S. Pat. No. 5,331,975 to Bonutti (see also Formationof Structural Grafts From Cancellous Bone Fragment, by P. M. Bonutti, M.J. Cremens, and B. J. Miller, Am. J. Ortop. Jul. 27, 1998: 499-502);each of the above references being incorporated in their entirety hereinby reference. This phase change would result in a construct that iscapable of both stabilizing the motion segment in the short run, andwould foster the development of a solid bony fusion over the long run.

To state the process in another way: the invention provides a pliableimplant that may be inserted into a cavity formed in a degeneratingdisc. The flexibility of the band allows it to be inserted through arelatively small opening in a disc or vertebral space. The band is thenpositioned so its fill opening may receive fill material. This materialis packed into the region interior to the band, causing the band toexpand and conform to the cavity formed in the disc or vertebrae. Fillmaterial is added until enough material is present to expand the disc tothe desired position. At this time, the band fill opening is closed, orallowed to self-seal to prevent egress of the fill material.

All US patents and applications and all other published documentsmentioned anywhere in this application are incorporated herein byreference in their entirety.

The invention in various of its embodiment is summarized below.Additional details of the invention and/or additional embodiments of theinvention may be found in the Detailed Description of the Inventionbelow.

The abstract provided herewith is intended to comply with 37 CFR 1.72and is not intended be used in determining the scope of the claimedinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of the invention is hereafter described withspecific reference being made to the following drawings.

FIG. 1 is a perspective view of a first embodiment of the invention.

FIG. 2 is a side view of the embodiment of FIG. 1.

FIG. 3 is a top view of the embodiment of FIG. 1.

FIG. 4 is a perspective view of an embodiment of the invention having anelongate fill opening.

FIG. 5 is a perspective view of an embodiment of the invention as it mayappear when used to replace a spinal disc.

FIG. 6 is a perspective view of an embodiment of the invention whereinthe band is a molded material.

FIG. 7 is a side view of an embodiment of the invention shown in thereduced state within a storage/delivery tool.

FIG. 8 is a side view of the embodiment shown in FIG. 7 wherein theinventive band is being removed from the storage/delivery tool.

FIG. 9 is a perspective view of an embodiment of the invention whereinthe inventive band has a woven, double walled configuration.

FIG. 10 is a perspective cut away view of the embodiment shown in FIG.9.

FIG. 11 is a perspective view of the embodiment of the invention shownin FIG. 9 wherein the inventive band further includes latitudinallyoriented support bands.

FIG. 12 is a perspective cut away view of the embodiment shown in FIG.11.

FIG. 13 is a perspective view of the embodiment of the invention shownin FIG. 11 wherein the inventive band further includes longitudinallyoriented support bands.

FIG. 14 is a perspective cut away view of the embodiment shown in FIG.13.

FIG. 15 is a side view of an embodiment of the invention wherein theinventive band has a single walled configuration.

FIG. 16 is a perspective view of an embodiment of the invention.

FIG. 17 is a top down view of an embodiment of the invention.

FIG. 18 is a side view of the embodiment of the invention shown in FIG.15 wherein the inventive band is shown is a partially reduced state.

FIG. 19 is a perspective view of a graft insertion tool suitable for usewith the inventive band.

FIG. 20 is a side view of the tool shown in FIG. 19.

FIG. 21 is a top down view of the tool of FIG. 19.

FIG. 22 is a side view of the tool of FIG. 19 seen dislocating thefibers of an embodiment of the inventive band.

FIG. 23 is a top down cut away view of a tool similar to the tool ofFIG. 19 as may be seen during graft insertion.

FIG. 24 is a perspective view of a portion of a spine wherein anembodiment of the invention is shown in place.

FIG. 25 is a cross-sectional view of a spinal body which includes anembodiment of the invention therein.

FIG. 26 is a close-up cut away view of a portion of the embodiment shownin FIG. 25.

FIG. 27 is a cross sectional view of a spinal segment which includes anembodiments of the invention being positioned thereabout.

FIG. 28 is a perspective view of the spinal segment shown in FIG. 27,wherein the embodiment of the invention is shown secured thereto.

FIG. 29 is a frontal view of a spinal segment shown in cross-section.

FIG. 30 is a frontal view of a spinal segment shown in cross-section,that includes an embodiment of the invention therewith.

DETAILED DESCRIPTION OF THE INVENTION

This invention may be characterized as an improvement of the inventor'sinventions described in U.S. Pat. Nos. 5,571,189 and 5,549,679, thedisclosures of which are incorporated herein by reference.

With reference to the Figures, FIGS. 1-3 illustrates an embodiment ofthe inventive implant 10 which consists of a sidewall band 12, which maybe characterized as being substantially tubular or ring like in shape.Preferably the band 12 is circular, however other elliptical shapes andother geometric shapes may also be used.

The band 12 is pliable and malleable before its interior space 14 (notshown in FIG. 2) is filled with the contents to be described. While inthis initial condition, the band 12 may be passed, in a collapsed state,through a relatively small tube or portal, such as recited in U.S. Pat.Nos. 5,571,189 and 5,549,679, the entire contents of both referencesbeing incorporated herein by reference. This feature is importantbecause access to the intervertebral disc is limited by anatomy andtherefore safety considerations direct us to use the smallest possibleportal of entry.

The band 12 may be constructed in a variety of ways. The band material16 may be etched, woven or braided material such as a weave of NITINOLfibers, or a form-molded material such as shown in FIG. 6. The materialor fabric 16 may be fluid impermeable or may be provided with a densitythat will allow ingress and egress of fluids and solutions and willallow the ingrowth and through-growth of blood vessels and fibroustissue and bony trabeculae. Where the material 16 is provided with sucha porous construction, pores or weave gaps are preferably tight enoughto retain small particles of enclosed fill material, such as ground upbone graft, other tissues or solid pieces of bone inducing material suchas hydroxyapatite or other biocompatible materials known to promote boneformation.

Where the material 16 of the band 12 is porous, such as in theembodiment shown in FIGS. 1-4, the pores or openings 18 of the fabricwill have a diameter of about 0.25 mm to about 5.0 mm. The size isselected to allow tissue ingrowth while containing the material packedinto the bag.

The material 16 of the invention must be flexible enough to allow it tobe collapsed and inserted into an opening smaller than the expanded bandsize. As may be seen in FIGS. 7 and 8, the band 12 is sufficientlyflexible so that it may be positioned into a holding chamber 50 of astorage tube or delivery device 52. Depending on the exact constructionof the band 12, the band may be compacted into a substantially smallerconfiguration than the band is capable of attaining when packed withgraft material. The delivery device however, is sized such that thedevice 52 may be inserted into a surgical opening wherein the band 12 isdrawn or pushed by plunger 56 out of the chamber 50, as indicated by thedirection of the arrow 54 as shown in FIG. 8. The band 12 may be used torepair and/or replace a vertebral disc 23 as may be seen in FIG. 5wherein the band is placed between adjacent vertebral bodies 24. Theband 12 may be inserted into a small opening in the annulus 21 of thedisc 23 and filled from within the disc. Alternatively, the band 12 maybe inserted within a hollowed region of a vertebra 24 to provide supportthereto, or may be utilized to replace an entire vertebral body 24. Inorder to ensure that the supportive quality of the band 12 ismaintained, the fill material used in conjunction with the band 12 ispreferably minimally elastic if at all.

Accordingly, the fabric band 12 may be formed from a polymeric materialto which a plurality of perforations are formed or added. It need not bewoven and may be molded, such as the embodiment shown in FIG. 6, orotherwise formed as is well known in the art. The preferred material mayprovide the ability to tailor bioabsorbance rates. Any suture-typematerial used medically may be used to form the band 12. The band 12 maybe formed of plastic or even metal. The band 12 could be formed from asolid material. The band 12 may be partially or totally absorbable,metal, plastic, woven, solid, film or an extruded balloon.

Preferably the material 16 is light, biocompatible, flexible and easilyhandled, but is also very strong in terms of resisting tension, and thusunlikely to rip or tear during insertion and expansion. When the deviceis expanded through insertion of fill material, such as is depicted inFIG. 23, the band 12 expands to a predetermined shape, and in doing so,it fills a previously excavated space 20 between the vertebral bodiesand/or within a vertebral body, such as may be seen in FIG. 5. Thisfilling results in the separation of the vertebral bodies 24 and resultsin the stabilization of the spinal motion segment, indicated generallyat 22.

As may be seen in FIGS. 1-2, and 4-5, the band 12 may be characterizedas having two ends 30 and 32. One or both ends 30 and 32 may be open asdefined by the band 12. As may be seen in FIG. 5, where the band 12 isutilized to replace a disc, the openings 30 and 32 are characterized asbeing less than the diameter of the surrounding vertebral bone, thusassuring containment of the graft material within the confines of theinterior 14 of the band 12. Where only a single end 30 or 32 is open,the material 16 which covers one or more of the openings is porous toallow for bone growth therethrough such as has been described above.

In addition, as may be seen in FIGS. 1-2 and 4-5, the band 12 may beequipped with a fill opening 26. The fill opening 26 must be largeenough to accommodate passage of fill material as well as the means ofplacing fill material into the interior space 14 of the band 12. Adevice which may be suitable for passing through the fill opening 26 forinsertion of fill material is described in co-pending U.S. patentapplication Ser. No. 09/608,079 as discussed above.

Preferably the opening 26 includes a means of preventing passage of fillmaterial out of the interior space 14. In the embodiment shown in FIG.4, the opening 26 includes an elongate passage 28 which may be tied offor otherwise sealed subsequent to insertion of the fill material.

As may be further seen in FIG. 5 when the band 12 is inserted betweentwo vertebra 24 or within a disc 23 or other hollowed region of anintervertebral space and filled with fill material, the fill materialwill push against the vertebral surfaces 40 which are adjacent to thetop 30 and bottom 32 of the band 12. The band 12 in combination with thevertebral surfaces 40 will contain the fill material within the interiorspace 14.

In the embodiment of the invention wherein the band material 16 is wovenfrom one or more fibers, the fibers may be composed of a variety ofmaterials as previously discussed. In the various embodiments shown inFIGS. 9-18, the band 12 may be constructed from one or more metal fiberssuch as, for example, NITINOL fibers 58, which have been woven orbraided together into the desired band shape. The use of a shape-memorymaterial such as NITINOL, or a material such as steel, titanium or othermetal, provides the band with sufficient mechanical strength to resiststretching or expansion as a result of the build up of graft material inthe interior 14. In addition, such shape-memory materials allow the bandto be collapsed prior to insertion, such as may be seen in FIGS. 7 and 8yet which will tend to reacquire its original shape once implanted.

FIGS. 9-18 depict a wide variety of band configurations. As may be seenin FIGS. 9-14 the band 12 may be characterized as a double walled bandor a loop of material folded back upon itself. Such a double walledconfiguration may be seen as having a inner wall 60 which is continuouswith the outer wall 62 and defining a toroid shaped space 63therebetween as seen in FIGS. 10 and 12.

As seen in FIGS. 12 and 14, the toroidal shaped space 63 may be filled,in whole or in part with pharmaceuticals for drug delivery to theimplantation site. The toroid space 63 may also be filled, subsequent toimplantation into a vertebral body with a biocompatible cement or othermaterial for providing the band 12 with additional support.

The double walled construction may provide the band 12 with increasedstrength to provide additional mechanical support for the graft materialcontained in the interior 14. In addition, the double walledconstruction may be configured to allow the various openings 18 of therespective walls 60 and 62 to partially overlap. As a result, the fibers58 of one wall, for example inner wall 60, may overlap the openings 18of the other wall, for example outer wall 62, thereby effectivelyreducing the size of the openings 18. As a result, a band 12 having adouble walled construction may not require any more fibers 58 than asingle walled band such as may be seen in FIGS. 15-18. However, it maybe desirable to provide a double walled band 12 with a denser weave offibers 58 for the purpose of providing the band 12 with greatermechanical strength.

Turning to FIGS. 11 and 12, a double walled band 12 may also include oneor more latitudinally disposed support members such as members 64 and 66shown. The individual support members 64 and 66 may be positioned in anymanner around the circumference of the band 12. In the embodiment shown,the members 64 and 66 are respectively disposed the first or top opening30 and the second or bottom opening 32. In addition the members 64 and66 are located between the inner wall 60 and outer wall 62. The members64 and 66 may be used to support the material 16 of the band by weavingthe fibers 58 about the members 64 and 66, such as may best be seen inFIG. 12.

The members 64 and 66 may be constructed from the same or differentmaterial as fibers 58. In addition, the members 64 and 66 may be one ormore wires or fibers woven or braided together and oriented in thelatitudinal orientation shown. Alternatively, one or more fibers may beequatorially oriented, or may be otherwise positioned anywhere aroundthe circumference of the band 12.

In addition to providing the band 12 with one or more latitudinallyoriented wires or members 64 and 66, the band may also include one ormore longitudinally oriented members 68 such as may be seen in theembodiment shown in FIGS. 13 and 14. In the embodiment shown, thelongitudinal members 68 vertically cross the band 12 to join thelatitudinal members 64 and 66. In addition, the longitudinal members 68are oriented substantially perpendicular to the latitudinal members 64and 66. The longitudinal members 68 provide the band with compressionsupport relative to the surrounding vertebra. The members 68 may bewoven into the fibers 58 or may be independent of the band's wovenconfiguration. In one embodiment where the band is equipped withlongitudinal members 68 as well as latitudinal members 64 and 66, thevarious members may act as a frame work which supports the woven fibers58 of the band 12.

As with the latitudinal members 64 and 66, the longitudinal members 68may be constructed out of any suitable material. Such material may bedifferent from or the same as the fibers 58. Additionally, the members68 may be characterized as one or more fibers 58 oriented in thelongitudinal direction shown.

In the various embodiments shown in FIGS. 15-18 it may be seen that theband 12, may be provided with only a single wall construction as opposedto the double walled construction previously described. As shown in FIG.15, because the single wall 70 is not a continuous overlapping loop ofmaterial such as may be seen in FIGS. 9 and 10, the single walled band12 shown in FIG. 15 may have openings 30 and 32 which have fairly jaggedor non-uniform edges 72. While the material 16 of the band 12 may notnecessarily be of sufficient hardness to penetrate the surroundingvertebral bone, the non-uniform nature of the edges 72 of the band 12,provides band 12 with surfaces which may tend to more readily engage thesurfaces of the surrounding vertebral bone, thereby preventing the band12 from shifting or otherwise moving during the graft injection processor thereafter.

As shown in FIGS. 15 and 16 the single walled band 12 may be configuredto have an essentially cylindrical shape. The cylindrical shape may becompressed into an elongated band such as may be seen in FIGS. 7 an 8prior to insertion into the body. However, the band 12 may be configuredto include other shapes, notably the rounded configuration shown in FIG.17, after the band 12 is inserted into a vertebral body. As may be seenin FIG. 18, the malleability of a single walled band is illustrated. Aswith all embodiments of the present invention, the band 12 may besignificantly distorted, collapsed or otherwise manipulated in order tocollapse the band into a reduced configuration such as may be seen inFIGS. 7 and 8. The present invention may be distorted in either or boththe radial and longitudinal directions while retaining its ability toexpand subsequent to insertion into the spinal area.

As shown in FIGS. 22 and 23, the band 12 is shown with a fill insertiontool 100 being inserted into the interior 14 of the band 12 by passingthrough one of the spaces or pores 18. The shape of the tool 100 as maybest be seen in FIGS. 19-21 is essentially an elongate shaft 104 havinga tapered or pointed distal end 102.

As is shown in FIGS. 19-21, an example of a fill insertion tool which issuitable for use in the various embodiments of the invention isillustrated. The tool 100 is further disclosed in a co-pending U.S.patent application Ser. No. 09/738,726 filed Dec. 15, 2000 and entitledTool to Direct Bone Replacement Material, to Kuslich et al., and is acontinuation in part application of U.S. patent application Ser. No.09/608,079 the entire contents of both being incorporated herein byreference.

The tapered distal end 102 of the tool 100 is sized to enlarge theopening 18 to allow passage of the tool 100 into the interior 14 bypushing aside the various fibers 58 as may best be seen in FIG. 22. Thefibers 58 are disposed to open the pore 18 from its nominal diameter ofabout 0.25 mm to about 5 mm to an enlarged opening sufficient to allowpassage of a portion of the shaft 104 therethrough.

The extent of tool penetration into the band interior 14 must besufficient to allow the side opening 106 to be fully contained withinthe band interior 14. The tool 100 may include more than 1 side opening106.

As shown in FIG. 23, the side opening 106 allows insertion of the bonegraft or other types of fill material 108 into the band interior 12. Thetool 100 may include a piston plunger or other means (not shown) forpushing fill material 108 from within the shaft 104, through the sideopening 106 and into the band interior 14.

If the internal diameter of the shaft 104 may be about 1.5 mm to 5 mmand is preferably approximately 2.5 mm in diameter. The length of theside opening 106 is preferably between about 1½ to 3 times the internaldiameter of the shaft 104.

The distal end 102 of the tool 100 is preferably angled to direct theflow and to break down any material that has packed back into morediscrete pieces.

Turning to FIG. 24 an embodiment of the band 12 is shown, wherein theband 12 includes at least one circumferentially disposed tightening orcinching member 65 shown. The cinching member 65 may be positioned inany manner around the circumference of the band 12 as previouslydescribed. In the embodiment shown, each member 65 extends about themid-portion 71 of the band 12 and includes ends 73 and 75 that extendoutward from one of the pores 18 where they may be pulled together andsecured or tied to one another in the manner shown. When the band 12 isproperly filled with fill material in any of the manners previouslymentioned, the ends 73 and 75 may be cinched together in order toconstrict the mid-portion of the band 12 so that the band 12 takes on aconcave shape, such as is shown. The concave shape may provide greatersupport and flexibility to the surrounding spinal bodies and to thespine itself. When ends 73 and 75 are pulled together and secured, notonly is the band provided with a concave shape, but any fill materialpositioned therein is pushed together for more effective engagement withsurrounding tissue as well as with itself and the band 12.

In the various embodiments described herein, it may be desirable tostimulate growth of bone through the band 12 or fill material 108contained therein, by direct or indirect application of electricalcurrent. In the various embodiments described herein, the band 12 mayinclude portions 81 and 83, where electrical leads 91 and 93 may bereadily attached, such as are shown in FIG. 25. Leads 91 and 93 are inelectrical communication with an electrical power source 95 whichprovides sufficient current to stimulate bone growth through andadjacent to the band 12. In at least one embodiment, the leads 91 and 93may be inserted through pores 18, as previously shown and described, todirectly stimulate the fill material 108.

The portions 81 and 83 may be part of a electrically conductive member85 which is disposed within the walls 60 and 62 of the band 12, such asis shown in FIG. 26. Alternatively, the entire band 12 is electricallyconductive, In yet another embodiment at least a portion of one or bothwalls 60 and 62 are electrically conductive and/or electricallyinsulated.

In an alternative embodiment of the invention shown in FIGS. 27 and 28,the implant 10 may be characterized as a linear member or members 200which is disposed about a vertebral disc 23 in a manner such as is shownin FIG. 27. The member 200 may be a one or more of a combination ofstrands, threads, fibers, cords or other substantially linear portionsof material which include a first end 202 and a second end 204 that arecapable of being tied or otherwise secured together. Preferably, themember 200 has a height sufficient to cover the entire exposed surfaceof the disc 23. Some examples of materials which are suitable for use asmember 200 or in its construction include, but are not limited to:Secure Strand available from Smith & Nephew Inc., THE LOOP.υ., availablefrom Spineology Inc., and Songer Cable from Medtronic Inc.

In some embodiments of the invention, one of which is shown in FIG. 28,the member 200 may be constructed of the same material 16 as thepreviously described embodiments of the invention shown in FIGS. 1-26,and include a plurality of pores or openings 18. Once secured about thedisc 23, the member 200 may be further cinched or otherwise tightenedabout the disc 23 as is shown in FIGS. 29 and 30. By tightening themember 200 about the disc 23, the disc 23 is compressed in order toinvaginate the annulus 21 toward its center thereby tightening theannulus fibers. Such tightening will stabilize the spinal motion segment22 and thereby stiffen that portion of the spine.

In FIG. 29 the annulus 21 of a disk 23 is shown within a spinal motionsegment 22 prior to the securement and tightening of member 200thereabout. It is shown that the annulus 21 of the disk 23 has apredetermined height 206 and a predetermined circumference 208. When themember 200 is disposed and subsequently tightened about the annulus 21,such as is shown in FIG. 30, the circumference is reduced as indicatedat reference numeral 208′ while the height of the disk is made greateras is indicated at reference numeral 206′.

By securing the ends 202 and 204 of the member 200 about the disc, themember 200 forms a substantially continuous band similar to thatpreviously described. When secured about a disc the member 200preferably has a substantially concave appearance, relative to thesurrounding spinal bodies, such as is shown in FIG. 28. When securedabout the disc 23, the disc 23 may be further treated with additionaltherapeutic agents, including fill material via the pores or openings18, in the manner previously described in relation to the embodimentsshown in FIGS. 1-26.

In addition to being directed to the specific combinations of featuresclaimed below, the invention is also directed to embodiments havingother combinations of the dependent features claimed below and othercombinations of the features described above.

The above disclosure is intended to be illustrative and not exhaustive.This description will suggest many variations and alternatives to one ofordinary skill in this art. All these alternatives and variations areintended to be included within the scope of the claims where the term“comprising” means “including, but not limited to”. Those familiar withthe art may recognize other equivalents to the specific embodimentsdescribed herein which equivalents are also intended to be encompassedby the claims.

Further, the particular features presented in the dependent claims canbe combined with each other in other manners within the scope of theinvention such that the invention should be recognized as alsospecifically directed to other embodiments having any other possiblecombination of the features of the dependent claims. For instance, forpurposes of claim publication, any dependent claim which follows shouldbe taken as alternatively written in a multiple dependent form from allprior claims which possess all antecedents referenced in such dependentclaim if such multiple dependent format is an accepted format within thejurisdiction (e.g. each claim depending directly from claim 1 should bealternatively taken as depending from all previous claims). Injurisdictions where multiple dependent claim formats are restricted, thefollowing dependent claims should each be also taken as alternativelywritten in each singly dependent claim format which creates a dependencyfrom a prior antecedent-possessing claim other than the specific claimlisted in such dependent claim below.

1. A method for repairing or replacing the nucleus of a spinalintervertebral disc, comprising: providing nuclear replacement fillmaterial; providing a generally flexible mesh member sized to fit andexpand transversely into a hollowed region of an intervertebral space,the mesh member defining an interior space, the mesh member constructedand arranged to expand from a reduced state to an expanded state by theintroduction of the fill material into the interior space, the meshmember including at least one fill opening through which the fillmaterial may be introduced into the interior space; inserting the meshmember into the intervertebral space through a small portal in theannulus; and inserting the fill material into the interior space of themesh member through the at least one fill opening using a fill tubehaving a means for deflecting the fill material at an angle from alongitudinal axis of the fill tube such that the fill material applies aforce within the mesh member sufficient to stabilize the intervertebralsegment.
 2. The method of claim 1 further including radially containingthe fill material.
 3. A method for repairing or replacing the nucleus ofa spinal intervertebral disc, comprising: providing a generally flexiblemesh member sized to fit and expand transversely into a hollowed regionof an intervertebral space, the mesh member defining an interior space,the mesh member including a plurality of pores, the plurality of poresbeing sized to allow ingress and egress of liquids, solutions or smallparticle suspensions and ingrowth of fibrous elements into and throughthe mesh when the mesh is positioned in the hollowed region of anintervertebral space, the plurality of pores being sized to retain thefill material within the interior space of the mesh member, the meshmember including at least one fill opening through which the fillmaterial may be introduced into the interior space, the at least onefill opening comprising at least one of the plurality of pores insertingthe mesh member into the intervertebral space; and inserting the fillmaterial into the interior space of the mesh member through the at leastone fill opening using a fill tube having a means for deflecting thefill material at an angle from a longitudinal axis of the fill tube suchthat the fill material applies a force within the mesh member sufficientto stabilize the intervertebral segment.
 4. A method for repairing orreplacing the nucleus of a spinal intervertebral disc, comprising:providing a generally flexible double walled mesh member sized to fitand expand transversely into a hollowed region of an intervertebralspace, the double walled mesh member defining an interior space anddefining a toroidal space between the inner wall and outer wall, themesh member including at least one fill opening through which the fillmaterial may be introduced into the interior space, and at least onefill opening through which fill material may be introduced into thetoroidal space, the mesh member constructed and arranged to expand froma reduced state to an expanded state by the introduction of fillmaterial into the interior space; inserting the mesh member into theintervertebral space; inserting the fill material into the interiorspace of the mesh member through the at least one fill opening; andinserting fill material into the toroidal space of the mesh member suchthat the filled toroidal space provides additional strength and radialsupport.
 5. A method for repairing or replacing a weakened vertebralbody, comprising: providing a generally flexible mesh member sized tofit and expand transversely into a hollowed region of a vertebral body,the mesh member defining an interior space, the mesh member constructedand arranged to expand from a reduced state to an expanded state by theintroduction of fill material into the interior space, the mesh memberincluding at least one fill opening through which the fill material maybe introduced into the interior space; inserting the mesh member intothe intravertebral space; and inserting a minimally elastic fillmaterial into the interior space of the mesh member through the at leastone fill opening using a fill tube having a means for deflecting thefill material at an angle from a longitudinal axis of the fill tube suchthat the fill material applies a force within the mesh member sufficientto provide support to the weakened vertebral body.
 6. A method forrepairing or replacing a weakened vertebral body, comprising: providinga generally flexible mesh member sized to fit and expand transverselyinto a hollowed region of a vertebral body, the mesh member defining aninterior space, the mesh member including a plurality of pores, theplurality of pores being sized to allow ingress and egress of liquids,solutions or small particle suspensions and ingrowth of bony trabeculaeor fibrous elements into and through the device when the device ispositioned in the hollowed region of a vertebral body, the plurality ofpores being sized to retain the fill material within the interior spaceof the mesh member, the mesh member including at least one fill openingthrough which the fill material may be introduced into the interiorspace, the at least one fill opening comprising at least one of theplurality of pores; inserting the mesh member into the intravertebralspace; and inserting a minimally elastic fill material into the interiorspace of the mesh member through the at least one fill opening using afill tube having a means for deflecting the fill material at an anglefrom a longitudinal axis of the fill tube such that the fill materialapplies a force within the mesh member sufficient to provide support tothe weakened vertebral body.
 7. A method for treating spinal disorderscomprising: creating a surgical portal; removing tissue to create ahollowed region within a spinal segment; providing a generally flexiblemesh member compacted to fit into a small delivery device; inserting theflexible member into the hollowed region by introducing the deliverydevice into the surgical portal; deploying the flexible member into thehollowed region such that it expands to a larger dimension than thesurgical portal and conforms to the hollowed region; and inserting fillmaterial into the interior space of the flexible member through the atleast one fill opening using a fill tube having a means for deflectingthe fill material at an angle from a longitudinal axis of the fill tubesuch that the fill material applies a force within the mesh member.